In glassware forming machines, moulds are used both for shaping the finished article and for preliminary shaping of the glass to form parisons which are then transferred to further moulds. All these moulds need to be maintained in a particular temperature range to ensure correct operation of the machine since, if the moulds become too hot, the glass will stick to them whereas, if the moulds become too cold, the glass will not be correctly shaped. To enable the temperature of the moulds to be controlled, glassware forming machines comprise mould cooling means operable to blow cooling air over the moulds. The cooling means must be controlled so that it cools the moulds sufficiently but not excessively. At present, the cooling means is controlled by an operator by a trial-and-error method so that incorrectly made articles are produced until the operator finds the correct setting for the cooling means.
It is an object of the present invention to provide a mould arrangement in which an electrical temperature sensing device mounted on a mould portion is used to generate a signal which automatically causes a portion of the operation of the machine, e.g. the operation of the cooling means, to be controlled in accordance with the value of the signal.
The use of electrical temperature sensing devices in mould portions presents certain problems. The electrical connections to the device need to be protected from excessive heat and it is desirable if the connections are readily disconnectable so that mould portions can be changed. If flexible wires are used for forming the electrical connection, there is considerable danger that they will be exposed to excessive heat and they may be difficult to disconnect rapidly. On the other hand, if the electrical connections are made through the mechanical mechanism for opening and closing the moulds, the mechanical movements cause considerable electrical noise in the circuit due to the movements of the mould portion and the holders.